36 weeks high amniotic fluid.

Had my 36 week appointment today with the midwife ( mines.gone for the month so saw her partner today). This is my 4th baby. 1st boy.and 1st time dealing with a midwife. The midwife was feeling my belly taking her measurements. Then tells me she would like to send me for an ultrasound as she feels I might have polyhydramnios ( never head of this before ) she said I definitely feel like I have a lot of fluid. ( everyone tells me I look really big this time around and think baby boy is gonna be a lot bigger then my girls due to.the size) I have been saying I feel like I have more fluid then baby. But never thought to mention it. I go tuesday for an ultrasound to measure my fluid levels. If I do have polyhydramnios. What exactly does that mean for me and baby? And what is typically done about it? I wont be seen again until im 38 weeks. When my midwife returns. But was told once my results are in she will call me and go over her findings and what not. ( she also never really explained anything about this just that it means high levels of fluid.)